Micro shear bond strength of mineral trioxide aggregate to different innovative dental restorative materials.

The objective of this in vitro study was to investigate the micro shear bond strength (µSBS) of mineral trioxide aggregate to four different restorative materials. Sixty mineral trioxide aggregate (MTA) samples were randomly assigned into four experimental groups based on the restorative materials used: nanohybrid resin composite as a control, giomer, alkasite and ormocer. µSBS samples were prepared for each group (n = 15). These samples were then submitted to a µSBS test (crosshead speed, 0.5 mm/min). The resulting data were statistically analyzed by one-way analysis of variance (ANOVA), Levene, and Bonferroni tests (α = 0.05). The bond strength of the alkasite group was statistically significantly higher than all the tested groups (p<0.05), while there were no significant differences between the nanohybrid resin composite, giomer, or ormocer groups (p > 0.05). Within the limitations of this study, alkasite restorative material could be a promising material when placed over MTA.

The effects of applying a novel cleaner on the bonding strength of zirconia surfaces.

This study evaluates how pre-treatment with an MDP-containing cleaning agent (Katana Cleaner, Kuraray) influences the micro-shear bond strength (µSBS) of saliva-contaminated zirconia when used with universal adhesive (UA) systems. Rectangular specimens (2 mm × 12 mm × 15 mm) were obtained (IPS, e.max ZirCAD, MO, B65L17, Ivoclar Vivadent) and divided into three groups; a non-contaminated group (control group)(CON), a contaminated and cleaned with isopropyl alcohol group(ISP), and lastly, a group contaminated and cleaned with an MDP-containing cleaning agent(KAC). Each group was then subdivided into three subgroups according to the UAs used (n = 12). Composite cylinders were prepared and bonded to each surface with Panavia V5 (Kuraray, Noritake Dental). A µSBS test was performed and the data were evaluated with the two-way analysis of variance (two-way ANOVA) and multiple comparisons test (α = 0.05). The highest µSBS values were obtained in the non-contaminated group (p < 0.001), regardless of UAs. All subgroups showed lower µSBS values after saliva contamination, but KAC resulted in significantly higher µSBS values than 99% isopropanol (p < 0.001). Overall, the lowest µSBS value was obtained with 99% isopropanol. The KAC-Clearfil UA subgroup resulted in statistically significantly higher µSBS values than the other UAs (p = 0.035 and 0.007), although all three UAs resulted in sufficient µSBS values. This study revealed that applying KAC followed by a UA containing phosphate monomers produces promising results for improving µSBS values of zirconia, greater than results using 99% isopropanol.Clinical relevance: An MDP-containing cleaning agent followed by a phosphate monomer containing a universal adhesive is a promising method to obtain acceptable bonds with saliva-contaminated zirconia ceramics.

Two-year evaluation of porcelain laminate veneers using FDI criteria.

PURPOSE: The use of porcelain laminate veneers (PLVs) is a minimally invasive technique that is often used in restorative dentistry due to esthetic considerations. The aim of this study was to evaluate PLVs according to the Fédération Dentaire Internationale (FDI) World Dental Federation clinical criteria. MATERIALS AND METHODS: This clinical study included 11 patients (7 female and 4 male) who had been admitted to the Usak University Faculty of Dentistry between February 2019 and February 2021. Before taking part in the study, patients were informed about alternative treatment procedure options. A total of 30 PLVs were fabricated and cemented, and patients were evaluated according to the FDI criteria (with a follow-up after 2 years). RESULTS: Restorations were evaluated by two trained researchers. During the follow-up evaluation, no fractures or cracks were observed in any restoration. Further, 73% (n = 22) of the PLVs had perfect marginal adaptation and only 27% (n = 8) had small marginal fractures that could be removed by polishing. Moreover, 57% (n = 17) of the PLVs were evaluated as a good color match (no difference in shade and/or translucency), whereas 33% (n = 13) had only minor deviations. In periodontal examinations, 23% (n = 7) of the PLVs had no plaque, inflammation, or pockets, whereas 77% (n = 23) had minor plaque inflammation and no pocket development. CONCLUSIONS: As there were no fractures, fails, or need for removal of the restorations after 2 years, PLVs showed clinically satisfactory performance. The performance of PLVs can be considered highly favorable due to the minimally invasive and periodontally-compatible nature, with a good color match when carefully planned.

The effect of different energy levels of the Er: YAG laser on the repair bond strength of a nanohybrid composite resin.

This study evaluates the durability of repair microshear bond strength (µSBS) of nanohybrid composite resins which surfaces are treated with different laser parameters and bur. A total of 240 nanohybrid composite resin disk shaped specimens were prepared. Then, specimens were divided into eight test groups as regards to surface treatment types (Erbium (Er:YAG) laser with seven different parameters and bur). Half of the specimens in each group were subjected to 5000 thermal cycling (TC) and the other half to 20,000 TC. Universal testing machine was used for µSBS test. The data were analyzed with a two-way analysis of variance and Tukey test. Among the specimens treated with ER:YAG laser+5000 TC, we detected the highest mean µSBS test values in the subgroups L200 and L250. Among the specimens treated with ER:YAG laser+20,000 TC, the highest mean µSBS test values were seen in the L200 subgroup. The µSBS values after the 20,000 TC were significantly lower than those after 5000 TC for all different treatment types. Thermal cycling and laser energy levels have effects on repair µSBS. Considering the bond strength and durability it seems more effective to use Er:YAG laser at 200 mJ. To repair an aged nanohybrid composite resin, Er:YAG laser surface treatments may provide some benefits by acquiring a reliable bond strength with durability. This study may give information on which parameters are more suitable to use Er:YAG laser for the repair of nanohybrid composite resins.

The effect of composite placement technique on the internal adaptation, gap formation and microshear bond strength.

Purpose: This study aimed to compare the efficiency of placement technique on internal adaptation, gap formation and microshear bond strength (SBS) of bulk-fill composite resin materials. Materials and methods: Standardized class V cavities were prepared for microcomputed tomography (mCT) test and divided into four groups (n=12) as follows: Group SDR: Smart Dentin Replacement system/bulk fill; Group SF2: Sonic-Fill system/bulk fill sonic-activated composite placement system; Group CHU: Herculite-XRV-Ultra composite resin inserted with Compothixo/sonic-vibrated composite resin placement system; Group HIT: Herculite-XRV-Ultra composite resin applied with incremental technique. Self-etch adhesive (Optibond-XTR) was used for bonding in all groups. After 10000 thermocycling, mCT scans were taken to reveal gap formation at the toothrestoration interface and universal testing machine was used to test microshear bond strength SBS values (n=10). ANOVA, post-hoc Bonferroni and Tukey HSD tests were used for evaluating the gap formation and SBS values p=0.05. Results: SF2 and CHU showed the best adaptability compared with both SDR and HIT. The difference between groups SDR and HIT was statistically significant (p<0.05).SBS values were found to be the highest for SF2, and the lowest for HIT groups (p>0.05). Conclusion: Bulk-fill composite resins placed either with sonic-activated or sonic-vibrated instrument demonstrated better adaptability, less gap formation and higher bond strength than both the bulk-fill flowable composite and conventional incremental techniques.

Bond strength of metal brackets to feldspathic ceramic treated with different surface conditioning methods: an in vitro study.

PURPOSE: To compare MEP which is originally manufactured for increasing bond strength between organic resins and ceramic with conventional surface treatment methods in preparation of leucite-reinforced FC surfaces regarding shear bond strength (SBS) of stainless steel brackets and the mode of bond failure. MATERIALS AND METHODS: Forty specimens that were fabricated from FC material and glazed were randomly assigned to four surface conditioning methods: (1) CoJet Sand; (2) MEP; (3) HF acid etching followed by silane coupling agent; (4) Diamond bur followed by silane coupling agent. The SBS was determined using universal testing machine. Bond failure sites were classified according to Adhesive Remnant Index (ARI). RESULTS: No statistically significant difference (p less than 0.05) was found in SBS between the groups while significant intergroup differences were detected concerning ARI scores (p less than 0.001). Group 1 had ARI score 1 and 2 indicating mode of failure at the adhesive interface with greater percentage of the adhesive left on bracket base. The other groups had higher frequency of ARI score 3 and 2. The quantity of the ARI retained on the ceramic surface was highest in Group 3, followed by Group 4 and Group 2. CONCLUSION: MEP can be a suitable alternative for bonding metal brackets to FC surface.

Effect of cement color and tooth-shaded background on the final color of lithium disilicate and zirconia-reinforced lithium silicate ceramics: An in vitro study.

OBJECTIVE: To evaluate the translucency and effects of different cement colors on the final shade of lithium disilicate ceramics (LDS) and zirconia-reinforced lithium silicate ceramics (ZLS) over an A1 and A3 tooth-shaded background. MATERIALS AND METHODS: Eighty-eight rectangular-shaped specimens were sliced from LDS and ZLS blocks. The final thickness of the specimens was set at 0.8 ± 0.01 mm. Spectrophotometric measurements for the translucency were taken against black and white backgrounds. Composite resin tooth-shaded background disks were fabricated in two shades (A1 and A3), as were resin cement disks (opaque and translucent) (n = 11). Next, the ceramic specimens and tooth-shaded backgrounds were connected with glycerin, and baseline measurements were taken. These measurements were used as a reference. Then, the ceramic specimens, cement specimens, and tooth-shaded backgrounds were connected together with glycerin, and a second set of measurements was taken. The CIEDE2000 (ΔE00 ) color formula was used to calculate the translucency and color differences. A Mann-Whitney U test was also performed for the translucency, and a three-way ANOVA (analysis of variance) test was performed for the ΔE00 values (α = .05). RESULTS: The LDS and ZLS groups had similar translucency (P = .055). The ΔE00 values of the specimens were significantly affected by the cement color and tooth-shaded backgrounds in the LDS and ZLS groups (P < .05). Using the opaque cement color resulted in statistically significant differences against the light and dark (A1 and A3) tooth-shaded backgrounds in both the LDS and ZLS groups (P = .022 and P = .006). CONCLUSIONS: The material type did not affect the translucency or final color. However, the cement color did affect the final shade when thin ceramic restorations were used. CLINICAL SIGNIFICANCE: It should be noted that the cement color and tooth-shaded background used may change the final color of thin high translucency ceramic restorations that contain lithium disilicate and zirconia-reinforced lithium silicate.